Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
iil. 
12. 
14. 
18. 
15. 
16. 
17. 
18. 
19. 
SEMINULA, McCoy. 
Page 781. 
SEMINULA TRINUCLEA, Hall. 
Dorsal view of a strongly trilobed internal cast; showing the char- 
acter of the muscular area. 
St. Louis group. Harrison county, Indiana. 
Ventral view of an internal cast. 
St. Louis group. Spergen Hill, Indiana. 
A view of the hinge-plate; showing its subquadrate outline and the 
prolongation of the crural lobes. » 3. 
SEMINULA sUBQUADRArA, Hall. 
A dorsal view of conjoined valves. 
Chester limestone. Crittenden county, Kentucky. 
An anterior view of the hinge-plate; showing the visceral foramen 
and the elevation of the crural lobes. > 3. 
St. Louis limestone. Pella, Towa. 
SEMINULA suBTILITA, Hall. 
A view of the hinge-plate; showing its form, concave upper face and 
the visceral foramen. X 3. 
Dorsal view of a large individual with normal proportions. 
Coal measures. Chariton county, Missouri. 
A preparation showing the structure of the brachidium. > 3. 
Coal measures. Winterset, Iowa. 
The interior of an elongate and thickened pedicle-valve; showing the 
deep excavation of the muscular scars. 
Coal measures. Near Kansas City, Missouri, 
228 
